Energy transport simulation for graded HBT's: importance of setting adequate values for transport parameters

Kazushige Horio, Tadayuki Okada, Akio Nakatani

Research output: Contribution to journalArticle

7 Citations (Scopus)


An energy transport simulation method for graded AlGaAs/GaAs heterojunction bipolar transistors (HBT's) is presented in which Al composition-, doping density-, and energy-dependences of transport parameters are considered. For several representative Al composition and doping densities, parameters such as electron mobility, energy relaxation time, and upper-valley fraction are evaluated as a function of electron energy by a Monte Carlo method. For the other Al composition, these are determined by a linear interpolation method. Calculated cutoff frequency characteristics and electron velocity profiles are compared with those obtained by using more simplified approaches, demonstrating the importance of giving adequate transport parameters, particularly in analyzing graded band-gap base HBT's.

Original languageEnglish
Pages (from-to)641-647
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number4
Publication statusPublished - 1999 Jan 1


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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